MCG being used in place of microgram
Sometimes it’s hard to measure up. Or rather, it can be confusing.
An HSI member named Swamy sent us an e-mail with this question:
“1 mg is 1000 micrograms. The symbol for micro is the Greek letter, mu. mcg means millicentigram and is 10 times a microgram. But I am seeing mcg being used in place of microgram. Will you kindly explain?”
No problem. All you need to do is forget all about standard metric abbreviations. There! That was easy!
But it might not be easy for scientists who use the metric system daily. For them (and for Swamy), “mcg” correctly indicates “millicentigram.” And when they want to abbreviate “microgram,” they use “ug” (although the “u” actually looks like an “h” turned upside down).
Confused yet?
Here’s the simple explanation: At some point, the drug and supplement industries began using “mcg” to indicate “milligram.” It’s wrong – metrically speaking – but it’s widely accepted nonetheless.
Who decided to go with mcg and why they decided to do it is a mystery. Or it is to me. If any HSI members know the origin of this metric misstep, please send an e-mail and fill us in.
